JPH03150157A - Bag made of composite layer-polyethylene film - Google Patents

Abstract

PURPOSE:To obtain the bag excellent in impact resistance and non skip property by making the bag of the composite layer film composed of the film formed with specified composition and the film formed of low density-polyethylene. CONSTITUTION:The bag made of composite layer-polyethylene film is manufac tured of the film formed with the composite composed of one kind or at least two kinds of the high density polyethylene having the molecular weight of about 150,000 - 250,000, styrenebutadiene thermoplastic elastomer, ethylene/ethyl acrylate copolymer, ethylene vinyl acetate copolymer, and ethylene/ethylene propylene rubber acrylic acid copolymer, and the film obtained by forming low density-polyethylene. The film made of the composition improves remark ably the impact resistance of the bag, and simultaneously prevents the occur rence of linear cracks. Since it is composite layer incorporated with the low density-polyethylene film, the non slip property of the bag is further improved.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention is a multilayer polyethylene film bag-making method that uses high-density polyethylene (hereinafter referred to as HDPE) with a molecular weight of about 150,000 to 250,000 and a styrene-butadiene thermoplastic elastomer c or less. (hereinafter referred to as SBTR), ethylene ethyl acrylate copolymer (hereinafter referred to as E
EA), ethylene-vinyl acetate copolymer (hereinafter referred to as EVA), ethylene propylene rubber (hereinafter referred to as EPR), and ethylene-acrylic acid copolymer (hereinafter referred to as EAA). The present invention relates to a multi-layer polyethylene film bag made of a multi-layer film formed from a composite composition consisting of a film formed from a composite composition consisting of the above, and a film formed from a low-density polyethylene film. [Prior Art] Conventionally, bags made only of low-density polyethylene or bags made of multilayer polyethylene film made of two layers of low-density polyethylene and high-density polyethylene have been filled with approximately 15 kg or more per bag. It has been proposed as a bag for heavy packaging, and this author also aims to improve the impact resistance required for heavy packaging, expand the optimal temperature range of heat sealing for sealing the bag opening, and improve non-slip properties. Bags made from multi-layer polyethylene film consisting of a layer of low-density polyethylene and a layer of mixed high-density polyethylene, which is a mixture of high-density polyethylene and styrene-butadiene thermoplastic elastomer, and low-density polyethylene and vinyl acetate. We proposed a bag made of a multilayer polyethylene film consisting of a layer of a copolymer of polyethylene and a layer of mixed high-density polyethylene, which is a mixture of high-density polyethylene and a styrene-butadiene thermoplastic elastomer.
(Refer to Japanese Patent Application No. 164046 and Japanese Patent Application No. 15711. As a result of repeated research to provide bags suitable for
It was discovered that bags made from a film formed from a composite composition of one or more of A, EPR, and EAA have extremely good impact resistance and do not generate linear crazes. (Special Application No. 209506 of 1973)

[Problems to be Solved by the Invention] As mentioned above, according to the proposal in Japanese Patent Application No. 1973-209506, the impact resistance when used for bags, especially heavy packaging, was sufficiently satisfactory. As the content of bags increases, there is an increasing need to improve the non-slip properties of bags. [Means for Solving the Problem 1] As a result of intensive research to further improve the non-slip properties of the bag, which is the key idea mentioned above, the inventors found that HDPE and S
Bags made from a multilayer film made of a composite composition consisting of BTR, one or more of EEA, EVA, EPR, and EAA, and a film made of low-density polyethylene are impact resistant. The present invention was achieved by discovering that a bag with excellent non-slip properties as well as properties can be obtained. The high density polyethylene in the present invention has a molecular weight of 150,000~
The molecular weight is approximately 250,000, and particularly preferred is one having a molecular weight of approximately 190,000 to 220,000. The low density polyethylene in the present invention has a density of 0-91
~0.93, and refers to a homopolymer of ethylene or a copolymer of a small amount of a-olefin or vinyl acetate. In the present invention, S in SBTR is styrene or a polymer block mainly composed of styrene, and B is composed of butadiene or a polymer block mainly composed of butadiene. An example of the blending of the resin in the composite composition of the present invention is as follows. (1) HDPE 100 parts, SBTR10-35
parts, preferably 15 to 25 parts, EEA (comonomer 5
~30%) 1 to 35 parts, preferably 5 to 153°12) HDPE 100 parts, SBTR 10 to 35
parts, preferably 15 to 25 parts, EVA (comonomer-5
~30%) 1 to 35 parts, preferably 1 to 15 parts. 13) HD P E I OO section, SBTR10
~35 parts, preferably 15-25 parts, EPR (ethylene content 40-75%) 1-30 parts, preferably 5-15 parts. (4) HDPE 100 parts, SBTR10-35
preferably 15 to 25 parts, EAA (acrylic content 3 to 20%) 1 to 30 parts, preferably 5 to 15 parts. 15) HDPE 100 parts, SBTR10-35
Parts preferably 15 to 25 parts, EEAl to 20 parts, EVA
l ~208B (However, the total of LEEA and EVA is 1
~35 parts (preferably 5 to 15 parts)) In the film formed from the composite composition of the present invention, SBTR is dispersed in HDPE, and it is observed that, for example, EEA exists around the dispersed SBTR. In order to obtain the multilayer film in the present invention, two extruders are prepared, and the composite composition is produced from one extruder. Low-density polyethylene is extruded from another extruder, and the low-density polyethylene and the composite composition are separately supplied to a die attached to the extruder. A multi-layer blown film is made by inflation molding by merging together to form a multi-layer inside the gou, but at this time the extrusion temperature is 160°C.
-170°C, suitably for composite compositions at 200-220°C, etc. Any suitable method is adopted. In the present invention? In order to make a 1 m bag, it is preferable to use a composite composition layer of 70 to 130 g and a low density polyethylene layer of 15 to 45 u. The bag of the present invention can store any desired item, but it is especially suitable for heavy-duty packaging that stores a large amount of feed, grain, fertilizer, resins, chemicals, sugar, salt, and various other foods in one bag. Preferably used. The bag of the present invention is manufactured so that the film layer made of the composite composition is the inner layer of the bag and the low density polyethylene film layer is the outer layer of the bag. Heat sealing properties and non-slip properties are significantly improved. 1. The fact that the composite film formed from the composite composition of the present invention has extremely poor impact resistance can be easily understood by the following explanation. That is, I-
When SBTR is resin blended with IDPE, HDPE
It is recognized that the SBTR phase is dispersed in the relationship between the sea and the islands in tII, but in this case, the particle dispersion of the SBTR phase is relatively unstable, and the stability of film formation is not necessarily good. Ta. These I (EVA, which is a thermoplastic copolymer resin that is compatible with each of DPE and SBTR)
By blending one or more of EVA, EPR, and EAA (F) at the same time, this copolymer resin acts as a surfactant, and SBT is added to the HDPE phase.
The particle dispersion of the R phase is stabilized, and the stability of 112111 during extrusion processing is improved.Furthermore, the HDPE phase and the SBTR phase are immiscible, and there is no contact between the two phases at the interface! Also, HDPE and SBTR did not have sufficient performance.
EEA, which is a thermoplastic copolymer resin that is compatible with each. By blending one or more of EVA, EPR, and EAA at the same time, the HDPE phase and SBTR can be combined.
This acts to form an interfacial layer between the dispersed phases and strengthen interphase adhesion, making it difficult for cracks to occur in the film and significantly improving impact resistance. In this way, the impact resistance has been significantly improved and the occurrence of linear cracks has been reduced.This is a bag made from a multilayer film made of a composite composition film and a film molded from low density polyethylene. The impact resistance and linear crack C stuck characteristics described above were not impaired at all, and the non-slip properties were significantly improved. Example 1 Next, the present invention will be explained in more detail with reference to Examples. (1) Mirason ACE manufactured by Mitsui Polychemical Co., Ltd.
3ON (low density polyethylene/LDPE) thickness 20
0 copies of blown film -...8 (2)
The outer layer is the Mirason ACE3ON (LDPE) with a thickness of 30B, and the inner layer is a blend resin of 100 parts of Yaizex 8000F (1-IDPE) manufactured by Mitsui Petrochemical Co., Ltd. and 25 parts of Toughprene A (SBTR) manufactured by Asahi Kasei Corporation. A total thickness of 130B consisting of 100 parts of thickness
Two-layer film...B (3) The outer layer is the Mirason ACE3ON (LDP
E) has a thickness of 30 g, and the inner layer includes 100 parts of Santic #181 (HDPE) manufactured by Asahi Kasei Industries, Ltd. and 25 parts of the Tuffrene A (SBTR). Nippon Unicar Co., Ltd. 92EEA Copolymer DPDJ
A two-layer film with a total thickness of 130 g consisting of 100 parts thick blended resin with 14 parts 6182 (EEA)
...C (pulling) The outer layer is made of the above Mirason ACE3ON (LDPE) with a thickness of 30B, the inner layer is made of 100 parts of the above Santic #lat (HDPE), 25 parts of the above Toughprene A (SBTR), manufactured by Mitsui Polychemical Co., Ltd. Everflex #1905 (
A two-layer film with a total thickness of 130u consisting of a blended resin with a thickness of 10011 and 14 parts of EVA)...
・D(5)・The outer layer is the Mirason ACE3ON (LD
PE) thickness 30 times, the inner layer is
(HDPE) and 100 parts of the ToughBrain A (S
BTR) and 25 parts of EPR-EP manufactured by Mitsubishi Yuka Co., Ltd.
Thickness l of blended resin with 14 parts O2P (EPR)
Two-layer film with a total thickness of 130B made of OOU
...E(6) The outer layer is 30 parts thick of @Kimurason ACE3ON (LDPE), the inner layer is 100 parts of the above-mentioned Santic #181 (HDPE), 25 parts of #Balanced Tuffrene A (SBTR), and Dow Chemical. EAA Copolymer 455 (FAA) manufactured by Co., Ltd.
A two-layer film with a total thickness of 130 times consisting of 100 g of blended resin with 14 parts of...F
(1) The outer layer is the Mirason ACE3ON (LDP
50 parts of E) and the said Everflex #1905 (E
30 times thick, consisting of a blended resin with 50 parts of VA);
Inner layer is 100
A two-layer film with a total thickness of 130 μ, consisting of a blend resin of 100 μ, 25 parts of the Toughblen A (SBTR), and 14 parts of the EEA copolymer DPDJ61B2 (EEA).
...G(8) The outer layer is the Mirason ACE3
ON (LDPE) has a thickness of 30 g, and the inner layer includes 100 parts of the Santic #181 (HDPE), 25 parts of the Toughblen A (SBTR), 5 parts of the EEA copolymer PDJ6182 (EEA), and the Eva A two-layer film with a total thickness of 130 g consisting of 100 g of blended resin with 5 parts of Flex #l 905 (EVA) was obtained. As for the extrusion conditions at this time, for extruding low density polyethylene as the outer layer, the screw diameter is 55mm and the melting temperature is 160 to 170°C, and for extruding the composite composition as the inner layer, the screw diameter is 90°C. The melting temperature is 200-220
At 2.8 °C, blow ratio was 2.8 using a 1001 intestine two-layer die.
Then, the resins of both the outer and inner layers are combined into two layers in a die to form a blown film. These blown films (A to H) were cut to a length of 6,401,111 mm, and the portion that would become the bottom was heat-sealed with an impulse sealer to obtain a bag. 20 kg of advanced chemical fertilizer was put into this bag and the opening was heat-sealed to prepare a test bag for a drop test. The physical properties of these films A to H are shown in the table, and a graph showing the heat seal strength at the heat seal part of bags made with films A to H and the relationship between the heat seal tensile impact strength and the heat seal temperature is shown. In the graphs shown in FIGS. 1 to 8, the curve connecting the x marks with a dotted line indicates the tensile impact strength of the heat-sealed portion, and the curve connecting the O marks with a solid line indicates the heat-sealing strength. Note: The drop test is performed as follows: The drop height is 1.5 m, and the floor surface is a concrete floor with IO shoes.
This is a floor surface with a board in close contact with it, and the number of test bags is 5. Fs
The following test order is: First side: 10 times on the back side: 10 times on the side; One side: 5 times on the opposite side; 5 times on the opposite side: 5 times vertically. Perform 5 times in a row. The test result of no bag breakage indicates that none of the 5 bags in the test were broken. C Mizushita Higashi 1) [Effect of the invention 1] In the present invention, the film made of the composite composition significantly improves the impact resistance of the resulting bag, and does not cause flocculent cracks. The f-resistance is equivalent to that of conventional bags.
If li-impact resistance is acceptable, the film thickness of the bag can be made thinner, which greatly contributes to resource conservation.Also, since the suitable temperature range for heat sealing has been expanded, the heat sealing can be stabilized when sealing the bag. This makes it easy for bag users to heat-seal themselves when filling the contents, and the heat-sealing strength is stable and reliable, and the film has a relatively soft stiffness. This improves the suitability for automatic packaging in automatic filling machines.In addition, since it is a multi-layer with low-density polyethylene film, these properties are not impaired at all, and the non-slip properties of the bag are further improved. In particular, it has the advantage that the ratio of EVA added to low-density polyethylene can be adjusted arbitrarily, and it has become possible to completely prevent bags from collapsing during transportation.

[Brief explanation of the drawing]

The attached drawings are graphs showing the heat-seal strength of the heat-sealed portion of bags made with the film shown in Example No. 1, as well as the relationship between the tensile impact strength of the heat-sealed portion and the heat-seal concentration. Film A graph, 2nd
The figure is a graph for film B, Figure 3 is a graph for film C, Figure 4 is a graph for film D, and Figure 5 is a graph for film E. 6 is a graph for film F, FIG. 7 is a graph for film G, and FIG. 8 is a graph for film H. Dotted line: Tensile impact strength of heat-sealed part (kg-c) Solid line: Heat-sealed tensile strength (kg/15-) Patent applicant Nippon Matai Co., Ltd. Relationship with the Haka 1 person incident Patent applicant

Claims (1)

[Claims] (1) High-density polyethylene (HDPE) with a molecular weight of approximately 150,000 to 250,000, styrene-butadiene thermoplastic elastomer (SBTR), ethylene-ethyl acrylate copolymer (EEA), and ethylene-vinyl acetate copolymer (EVA). ), ethylene propylene rubber (EPR)
, ethylene acrylic acid copolymer (EAA). Multi-layer polyethylene film bag.